Percussive tool



Mmh 1, 1932. J A N+ 1,847,085

PERCUSSIVE TOOL Filed Nov. 2, 1926 A TTORNEV Patented Mar. l, 1932UNITED STATES PATENT OFFICE i JAMES A.

'.FLINT, OF DENVER., COLORADO, ASSIGNOR TO THE TRAYLOR 'VIBRATOBCOMPANY, OF DENVER, COLORADO, A CORPORATION OF COLORADO PERCUSSIVE TOOLApplication l'ed November 2, 1926.. Serial No. 145,787.

This invention relates to percussive tools, such for example, as rockdrills, riveting hammers, chippin hammers and the like.

The object of t e invention is to provide 5 an improved and simpliedform of tool capable of operation at a very high rate of speed .so as toenable repeated blows or impacts to be struck with a rapidity greatly inexcess of that obtainable with existing tools.

The invention essentially comprises an electromagnetic motor oroperating means and a resilient means cooperating therewith', the motorand resilient means acting together in synchronism to produce andmaintain a suitable striker or hammer member in vibration orreciprocatory movement at a predetermined high frequency and with adesired or controlled amplitude of vibration.

The invention is illustrated in the accompanying drawing as applied to arock drill, the ligure bein a vertical, longitudinal section of thedrillg.

The particular construction shown comprises a substantially cylindricalcasing within which are enclosed the striker or hammer rod and themechanism for maintaining said rod in a state of vibration orlongitudinal reciprocation at a predetermined frequency and at a highrate of speed. This mechanism includes a resilient means normallyholding the striker or hammer rod in a neutral position but capable ofbeing deflected in either direction from said neutral position and whenso deflected tending to restore the striker rod to said neutralposition, and electromagnetic means for causing rapidly repeateddeflection of the resilient means, to thereby maintain the striker rodin vibration or reciprocation along its axis.

The striker rod (1) is arranged centrally of the casing (2) and isguided for axial vibration or reciprocation therein byy means of apartition (3) which may be integral with or secured to the casing in anysuitable manner intermediate the ends thereof. The rod is also guided atits upper end as will later ap ear.

ecured to the striker rod (1) above the partition (3) is a plate (4),which may be conveniently mounted upon the rod by means of screw threads(5) and held in the desired position by means of a lock nut (6).Interposed between the plate (4) and the partition (3) is a block orcylinder (7) of rubber, having a central aperture (8) to accommodate therod (l) Above the plate (4) is a second similar block or cylinder (9) ofrubber, which is interposed between the plate (4) and an upper plate(10) fitting within the upper part of the casing (2). This upper plate(10) is connected by means of a plurality of bolts (11) with thepartition (3), the heads of the bolts engaging the upper side of theplate and the lower ends thereof being threaded into the partition, thusproviding for adjustment of the position of the plate (10) relatively tothe partition (3). By thus adjusting the plate (10) relatively to thepartition the initial stress or compression under which the rubberblocks or cylinders are placed may be varied as desired.

Beneath the partition (3) is arranged the electromagnetic means formaintaining the striker rod in vibration. In the form shown shapedlaminated core (12) mounted in a suitable core holder (13) ofnon-magnetic material, which may conveniently be secured to'inwardlyprojecting lugs or supports (14) formed at the lower end of the casing(2). The core (12) is provided on the upwardly projecting arms or polesthereof with energizing coils (15). Above and suitably spaced from theupper ends of the poles of the core (12) is a reciprocable laminatedarmature (16) which may be mounted in a holder (17) of non-magneticmaterial, which is secured in any suitable manner to the striker rod (1)The armature (16) and the core (12) are suitably apertured to permit thepassage oi. the striker rod therethrough.

The coils (15) are connected with a suitable source of alternating orpulsating current, whereby the armature (16) is intermittently attractedtoward the poles of the core ('12) thereby moving the striker rod (1) inthe downward direction. This movement of the rod, through the plate (4)secured thereto, delects or compresses the rubber block or cylinder (7)between the plate and the partition (3) and thrs builds up in the rubberblock a restoring force which, when the attraction of the armaturetoward the poles of the core ceases between the alternations orpulsations of current, tends to restore the striker rod and the partscarried thereby upwardly to the neutral positions thereof. Due to theinertia of the striker rod and the parts moving therewith the rod andsaid parts will be carried upwardly beyond the neutral position and theupper rubber block or cylinder (9) will be deflected or compressedbetween the plate (L1) and the upper plate (10), building up in thisblock also a restoring force tending to restore the striker rod andparts carried thereby downwardly to the neutral position. This downwardmovement of the striker rod and parts carried thereby will be assistedby the attractive force of the core (12) upon the armature (16), and asthe striker rod and plate reach the neutral position the attractiveforce of the core on the armature, together with `the inertia of theparts will carry the striker rod and plate downwardly beyond the neutralposition, again dellecting or compressing the lower rubber block (7) andagain building up therein a restoring force for effecting the nextupward movement of the striker rod and parts connected thereto. Thisvibration or reciprocation of the striker rod will continue as long asthe current is supplied to the energizing coils.

It will be understood that the attractive forces are intermittentlyapplied to the armature (16) in such manner as to cause the striker rodto vibrate or reciprocate at a predetermined frequency, and that therubber blocks or cylinders (7 and 9) are so designed as to their sizeand resiliency as to also maintain the striker rod in vibration at thissame predetermined frequency. 'lhat is to say, the blocks or cylindersare so designed that when deflected or compressed in the mannerdescribed, restoring forces are built up therein of the necessarymagnitude to return the striker 4rod and parts carried thereby to the ineutral position in the same time as taken to move the rod and partsfrom said position. Thus the electro-magnetic means and said blocks orcylinders properly cooperate in synchronism with each other to maintainthe striker rod and associated parts in vibration or reciprocation atsaid predetermined frequency, and with a desired amplitude of vibration,which may be varied by varying the strength of the current supplied.

The rubber blocks or cylinders (7 and 9) are preferably placed under an.initial stress or compression, and this is effected by suitablyadjusting the bolts (11) so as to vary the distance between thepartition (3) and the upper plate (10) The lower end of the striker rod(1) is enlarged to provide an impact or hammer portion (18), and beneaththis hammer portion is mounted the chuck (19) within which the drillsteel (20) is arranged, the chuck receiving the impacts or blows fromthe striker rod. and imparting them to the drill steel. This chuck ismounted centrally in suitable bearing portions of a lower cap section(21), and an intermediate end section (22) which is suitably secured, asby means of screw threads (23), to the lower end of the casing (2), thecap section (21) in turn being suitably secured to the intermediatesection, as by means of screws (24).

The position of the armature (1(5) with respect to the poles of the core(12), and the position of the impact face of the hammer portion (18) ofthe striker rod with respect to the upper face of the chuck (19) may beadjusted or determined by rotational adjust ment of the striker rod,which by reason of the screw threaded engagement of this rod with theplate (4) held between the rubber blocks (7 and 9) will enable verticaladjustment of the rod to be effected. The relative adjustment of theparts is such that the impact or blow is always taken by the chuck (19),the armature not coming into Contact with the pole faces. The plate(l0)l and the upper block are removed to-permit access to the lock nut(6) to permit the desired movement of the rod and to lock the rod 1n itsadjusted position. The upper plate (10) may also have a splinedconnection with the striker rod to normally prevent rotation of thelatter and to hold the armature in proper relation to the pole faces.

Any suitable means may be provided for effecting rotation of the chuck(19) and drill steel mounted therein. In the form of means shown forthis purpose the reciprocating movements of the striker rod are utilizedto effect the desired rotation. Such means comprises a spindle (25)rotatably supported by the sections (21 and 22) and one of the lugs(14), and held in place by means of a threaded plug (26). Secured to thespindle (25) between the sections (21 and 22) is a pawl (27 adapted toengage ratchet teeth (28) formed on the chuck (19). Also sccured to thespindle (25) adjacent the lug (14) is an arm (29) which at its inner endis adapted to ceact with the cam-shaped portion (30) formed between thestriker rod proper and the hammer portion 18) thereof. Thus as thestriker rod reciprocates, the arm (29), spindle (25) and pawl (27) willbe oscillated about the axis of the spindle in one direction by. the cam(30) and in the other direction by a suitable spring, and during eachsuch oscillation the pawl will engage the ratchet teeth (28) and willimpart a partial rotation to the chuck and drill steel. It will beunderstood that the inner end of the pawl may be provided with ayieldable tooth portion` adapted to yield on the backward stroke of thepawl in order to pass the ratchet teeth. A suitable number of stoppawls, such as 31, may be provided mounted on studs (32) threaded intothe cap section (21) and engaging the ratchet teeth to prevent reverserotation of the chuck. v

Water may be supplied to the drill steel during cutting through asuitable pipe (33) connected to a channel (34) formed in the lower partof the intermediate section (22) and leading to an annular groove (35),formed partly in the upper portion'of the Chuck and partly in thesurrounding wall of the intermediate section (22). The water isconducted from said annular groove to the drill steel by means of holes(36) drilled in the chuck and leading into the upper end of the socketin the chuck in which the drill steel is mounted. Alternatively airunder pressure may be supplied through the pipe (33) for blowing out thedrill steel.

The air under pressure for blowing out the drill steel may be furnishedby the re ciprocating movement of the striker rod (l). For this purposethe upper end of the striker rod has secured thereto in any suitablemanner a piston member (37) which works within ya cylinder (38) formedin the'upper end. plate (39) secured to the upper end of the casing (2).rlhe outer end of the cylinder is closed by means of a screw threadedplug (40) having an outlet (41) connected with a suitable pipe (42) andprovided with a suitable check valve The piston provided with inletvalves (44) and t e end plate 39) is provided with suitable air inletopenings (45). Thus on the downward movement of the striker rod, airwill be drawn into the cylinder (38) through the valves (44) in thepiston, and on the upward movement of the rod this air will becompressed and forced out through the pipe (42) which may be suitablyconnected with the pipe (33) leading to the interior of the chuck member(19). It will be understood that by screwing down the plug (40) more orless-into the upper end of the cylinder (38) the pressure to which theair is compresd may be varied.

It will further be understood that in the case of a rock drill the samewill be provided with the necessary means for supporting or mounting thesame for use in the conventional manner well understood in this art, andthat in the case of other percussive tools suitable provision will bemade lfor holding or mounting the tools to permit proper operationthereof.

What I claim and desire to secure by Letters Patent is 1. A percussivetool, comprising in combination, a reciprocable striker member, anarmature secured to said member, electromagnetic means arranged to applyattractive forces to said armature at a predetermined frequency, to movesaid striker member in storing force acting in the same direction assaid attractive forces, said resilient means being designed and arrangedto maintain the striker member in reciprocatory movement at `apredetermined frequency in synchronism with the frequency of saidattractive forces..

2. A percussive tool, comprising in combination, a reciprocable strikermember, an armature secured to said member, electromagnetic meansarranged in electro-magnetic relation to said armature and adapted whenenergized to produce attractive forces effec-v tive upon said armatureto move the same at a predetermined frequency, a plate member secured tosaid striker member, rubber blocks disposed at opposite sides of saidplate member, and relatively stationary means engaging the oppositesides of said rubber blocks, said blocks being so designed that whencompressed due to movement of said striker member by saidelectro-magnetic means restoring forces will be alternately developedtherein such as to maintain said striker member in reciprocatorymovement at said predetermined frequency. 3. A percussive tool,comprising in combination, a casing, reciprocating parts reciprocablymounted within said casing, connected for movement as a unit, andincluding an armature and a striker member, electro-magnetic meanssupported within said casing in electromagnetic relation to saidarmature, and .resilient means within said casing con-y nected with one`of said reciprocating parts, said electro-magnetic means and saidresilient 4ment of said striker rod and developing a remeans actingjointly and in synchronism with each other to cause said reciprocatingparts to vibrate or reciprocate and to maintain them in .vibration orreciprocation at a predetermined frequency, a chuck member carried bysaid casing and positioned relatively to one end of said striker memberto receive blows or impacts therefrom, and air compressing means at theopposite end of said casing and operated by said striker member.

4. A percussive tool, comprising in combination, a casing, a strikermember reciprocably mounted within vsaid casing, an armature secured tosaid striker member, electromagnetic means mounted within said casingand arranged to apply electro-magneticimpulses to said armature at apredetermined frequency, a plate member secured to said striker member,rubber .blocks positioned at opposite sides of said plate member,stationary means within said casing engaging. the opposite faces of saidrubber blocks, the latter being so designed as to maintain said strikermember in reciprocatory movement at the said predetermined frequency,and a chuck member carried by said casing and positioned relatively toone end of said striker member to receive blows or impacts therefrom.

5. A percussive tool, comprising in combination, supporting means, astriker member reciprocably vmounted in said supporting means, anarmature secured to said member` electromagnetic means supporte-d bysaid supporting means in electromagnetic relation to said armature andadapted When energized to produce recurrent attractive forces effectiveupon said armature to move the same at a predetermined frequency, aplate member secured te said striker member, elastic masses disposed atopposite sides of said plate member, and relatively stationary meansengaging the opposite sides of said elastic masses, said masses being sodesigned that when compressed due to movement of said striker member bysaid electromagnetic means, restoring forces Will be alternatelydeveloped therein such as to maintain said striker member inreciprocatory movement at said predetermined frequency.

G. A percussive tool, comprising in combination, supporting means, astriker member reciprocably mounted in said supporting means, anarmature secured to said member` electro-magnetic means supported bysaid supporting means in electromagnetic relation te said armature andadapted when energized to produce recurrent attractive foices effectiveupon said armature to move the same at a predetermined frequency, aplate member secured to said striker member, elastic masses disposed atopposite sides of said plate member, and relatively stationar;v meansengaging the opposite sides of said elastic masses and relativelyadjustable to place said masses under a predetermined initial stress,said masses being so designed that when compressed due to movemcnt'ofsaid striker member by said electromagnetic means, restoring forces willbe al ternately developed therein such as to maintain said strikermember in reeiprocatory movement at said predetermined frequency.

7. A percussive tool, comprisingl in combination, a support,reciprocatory means mounted in said support, including a stri kermember, and constituting a predetermined mass to be vibrated,electromagnetic means mounted in said support in electromagneticrelation to a part of said reciprocatory means and adapted whenenergized to produce attrative forces effective upon said reciprocatorymeans to cause repeated movement thereof at! a predetermined frequency,and resilient means mounted in said support and connected with a part ofsaid reeiprecatory means, said resilient means being arranged to bedeflected in one direction from its neutral position by the movement ofsaid reciprocatory means by said' electromagnetic means and to bedeflected in the opposite direction by the inertia of said reciprocatorymeans, and being predesigned with respect to said predetermined massthat it is inherently capable under repeated deflection of developingWithin itself restoringr forces such as to maintain said reciprocatorymeans in movement at said predetermined frequency.

8. A percussive tool, comprising in combination, a support,reciprocatory means mounted in said support, including a striker member,and constituting a predetermined mass to ybe vibrated, a yvibratorymeans mounted in said support and connected with a part of saidreciprocatory means, said vibratory means being predesigned andconstructed so that it is inherently capable u;1- der repeateddel'leetioii in opposite directions of developing Within itselfrestoring` forces of such magnitude as to maintain itself and saidpredetermined mass in vibratory movement at a predetermined frequency,and elerztromagnetic means mounted in said support in electromagneticrelation to a part of said reciprocatory means and adapted whenenergized to produce actuating forces effective upon said reciprocatorymeans to repeatedly deflect said vibratory means.

9. A percussive tool, comprising in combination, a support,reciprocatory means mounted in said support, including a striker member,and constituting a predetermined mass to be Vibrated, vibratory meansmounted in said support and connected with a part of said reciprocatorymeans, means for placing said vibratory means in itself under apredetermined stress, said vibratory means being predesigned andconstructed When under said predetermined stress to be inherentlycapable of maintaining said predetermined mass in vibratory movement ata predetermined frequency, and electromagnetic means mounted in saidsupport in electromagneti;l relation to a part of said reciprocatorymeans and adapted When energized to produce recurrent actuating forceseffective upon said reciprocatory means to maintain said vibrator-ymeans in vibratory movement at said predetermined frequency.

lO. A pcrcussivc tool, comprising in combination, a support,reciprocatory means mounted in said support, including a striker memberand an armature, and constituting a predetcrinined mass to be vibrated,resilient means mounted in said support and connected with a part ofsaid reciproeatory means, said resilient means being predesigned andconstructed to be inherently capable in itself of maintaining saidpredetermined mass in vibratory movement at a predetermined frequency,and an electromagnet mounted in said support in electromagnetic relationto said armature and adapted when energized to produce recurrentattractive forces effective upon sid armature and upon said resilientmeans to maintain the latter in vibratory movement at-said predeterminedfrequency.

In testimony whereof I ax my signature.

JAMES A. FLINT.

